<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    * {
      margin: 0;
      padding: 0;

    }
    .wrapper {
      height: 100px;
      width: 100px;
      position: absolute;
      left: 50%;
      margin-left: -50px;
      background-color: black;
    }
  </style>
</head>
<body>
  <div class="wrapper"></div>
</body>
</html>